Flywheel kinetic accumulator

ABSTRACT

A flywheel kinetic accumulator provides an accumulator assembly, in which a flywheel that is mounted on roll bearings rotates about a rotation axis; the flywheel is axially supported by two sets of magnetic elements ( 16, 16′ ) facing each other, arranged in two parallel planes, along two circular paths having the same diameter; one set is connected to the accumulator assembly, and the other to the flywheel; the magnetic elements ( 16, 16′ ) of the two sets are arranged in rotation, such that when a magnetic element ( 16 ) of the one set is aligned with a respective magnetic element ( 16′ ) of the other set along an axis that is parallel to the rotation axis, all other magnetic elements ( 16, 16 ′) are offset with respect to one another in order to reduce/eliminate the magnetic forces acting in the direction opposite to the rotation direction (V).

The present invention relates to a flywheel kinetic accumulator.

It is known to use flywheel kinetic accumulators as an alternative toconventional electrochemical batteries, in order to store energyreserves where and/or when there is no electric power available.

See, for example, document US2011/0298293A1, which shows a version of aconventional accumulator.

A kinetic accumulator of the known type comprises first magnets attachedto a flywheel frame, and second magnets in rotating connection with theflywheel, these magnets being provided to magnetically lift the latter.Typically, the first and second magnets are arranged at regular distancewith respect to each other, around the revolution axis of the flywheel.

One of the drawbacks of this prior art relates to the magnetic forcesdeveloping from the motion of the second magnets, whereby in certainrotation steps these forces oppose the free rotation of the flywheel,thus braking it.

Clearly, this phenomenon is undesired, as this braking—or, in any case,slowing down—action corresponds to a lower amount of rotational kineticenergy stored.

In the above framework, the present invention proposes to provide aflywheel kinetic accumulator that allows to reduce or even eliminate theslowing down of the flywheel caused by the magnetic forces opposed tothe desired rotation direction, as a result of the offset arrangement ofits magnets.

This object is fulfilled by an accumulator according to claim 1.Preferred embodiments are shown in the subclaims.

The object of the present invention shall now be described in detailwith the aid of the drawings provided as an example, without limitation,in which:

FIGS. 1,2,3 show an exploded perspective view, an exploded side view andan assembled side view in axial section, respectively, of a flywheelkinetic accumulator, subject-matter of the present invention, accordingto a first embodiment of the invention;

FIG. 4 illustrates the detail regarding the area highlighted in FIG. 3;

FIG. 5 shows an enlarged exploded view of the detail in FIG. 4;

FIG. 6 shows a plan view of a lower assembly wall according to theorientation in FIG. 1, in which there is laid out also the perimeter ofa set of magnetic elements, associated with the flywheel;

FIG. 7 shows an enlargement of FIG. 6, in which there is clearly visiblethe offset arrangement of the magnetic elements;

FIGS. 8,9,10 show an exploded perspective view, an exploded side viewand an assembled side view in longitudinal section, respectively, of themain parts of a flywheel kinetic accumulator, subject-matter of thepresent invention, according to a second embodiment;

FIGS. 11,12 show two sectional top and bottom plan views, respectively,of the flywheel accumulator in FIGS. 8,9,10.

Referring to FIGS. 1-7, referral number 1 indicates as a whole aflywheel kinetic accumulator comprising an accumulator assembly 2, aflywheel 4, mechanical rolling means 6,8, and magnetic support means 10for the flywheel 4.

The accumulator assembly 2 defines an inner space 42 in which theflywheel is rotatable about a rotation axis R. This space 42 is openoutwards, i.e., it is not hermetically sealed.

Thus, the inner space 42 is substantially at atmospheric pressure; inparticular, it is neither pressurised nor under negative pressure withrespect to the external environment in which the flywheel kineticaccumulator 1 is operated.

The accumulator assembly 2 provides a pair of opposing assembly walls34,34′, specifically arranged at the “axial” (this term being used withreference to the rotation axis R of the flywheel) ends of the assembly2.

The inner space 42 is defined between the assembly walls 34,34′.

One or both assembly walls 34,34′ may consist of a magnetically inertmaterial, advantageously a polymer material optionally loaded withreinforcing fibres. Merely by way of example, the magnetically inertmaterial is a composite material based on polylactic acid (PLA) andglass fibre.

The assembly walls 34,34′ are connected by a plurality of columns orbearing members 46, having a cylindrical shape, for example.

The accumulator assembly 2 further provides a cylindrical assemblycasing 56 housing the flywheel 4. The inner space 42 is defined by acasing wall 48 of such casing 56.

The flywheel 4 provides a number of flywheel blades 50 radiallyextending outwards from the rotation axis R. For example, in theembodiment shown in FIG. 3 there is outlined at least a pair of thesediametrically opposed blades 50.

A free end 52 of at least one flywheel blade 50 is counter-shaped inrespect to a wall of the accumulator assembly 2 defining the inner space42, for example in respect to the casing wall 48.

In the embodiment in FIG. 3, the free end 52 of the flywheel blade 50defines a peripheral cavity 54, in which there is housed a portion 58having a radial recess towards the rotation axis of the aforesaid wallof the accumulator assembly 2.

The peripheral cavity 54 extends in a middle or central position of theflywheel blade 50, along a direction substantially parallel to therotation axis R.

The accumulator 1 may comprise a device for detecting the weight of theflywheel 4 (device not shown), releasably fitted through an accessopening 32 to the inner space 42, to detect the load resting on themechanical rolling means 6,8.

As a result, the detecting device according to this version may beintroduced in the inner space for either fine tuning or checking outperiodically the accumulator, and may be removed afterwards.

FIG. 4 clearly shows the access opening 32 made out of the assembly wall34 of the accumulator assembly 2. As mentioned above, the flywheel 4 islocated in the accumulator assembly 2 so as to rotate about the rotationaxis R, for example oriented in a substantially or generically verticaldirection, in a desired rotation direction V.

It is to note that for the purpose of the present invention, therotation direction V—be it clockwise or counter-clockwise—is irrelevant.

Advantageously, the flywheel 4 comprises a rotation shaft 26 connectingthe same with the accumulator assembly 2.

The rotation shaft 26 is engaged or fitted in the opposing assemblywalls 34, 34′, and axially protrudes beyond the flywheel blades 50, toengage the accumulator assembly 2.

A shaft end 26′ protrudes outside of the inner space 42, to connect theflywheel 4 with an external motor (not shown), for example by coupling.The shaft end 26′ passes through the whole thickness of the assemblywall 34′ and may possibly protrude outside of the assembly 2.

The mechanical rolling means 6,8 are mounted between the accumulatorassembly 2 and the flywheel 4 (and more specifically between therotation shaft 26 and said assembly 2), for guiding the rotation of thelatter.

The mechanical rolling means 6,8 provide spherical or cylindrical bodiesmade at least partially from a magnetically inert material, for examplea ceramic material.

More specifically, these bodies are integrated into bearings 60 mountedeither on the flywheel 4 or on the rotation axis 26, coaxially with therotation axis R. As regards the magnetic support means 10 of theflywheel 4, these means provide at least two sets 12,14 of magneticelements 16,16′ facing each other, these elements being arranged at adistance from each other around the aforesaid rotation axis R.

For example, the magnetic elements 16,16′ comprise a plurality ofpermanent magnets, for example in neodymium.

In the embodiment shown in the drawings, the sets 12,14 of magneticelements 16,16′ have the same polarity, so as to repel each other alongthe rotation axis R or parallel thereto.

In an embodiment not shown, the sets of magnetic elements may haveopposing polarities, so as to attract each other along the rotation axisR or parallel thereto.

In the outlined embodiment, the accumulator 1 provides an upper set 12and a lower set 14 of said elements—according to the orientation of theFigures.

Thus, the magnetic support means 10 are either assigned or designed tomagnetically support at least part of the weight load of the flywheel 4acting on the mechanical rolling means 6,8, and thus to partially orcompletely relieve the latter of the weight of the flywheel 4.

One set of magnetic elements 14 is connected to the accumulator assembly2 and the other set of magnetic elements 12 is connected to the flywheel4, and these sets define a magnetic support space 18 therebetween. Morespecifically, the magnetic elements 16,16′ identify magnet surfaces20,20′, facing each other and defining the magnetic support space 18.

The magnet surfaces 20,20′ have substantially the same conformation(e.g., the same surface area and/or the same external geometry) for bothsets 12,14. In the example shown, the magnet surfaces 20,20′ arecircular. Each of the magnetic elements 16,16′ has a cylindrical shapeand is the same size in respect to the other, and the two sets 12,14 ofmagnetic elements 16,16′ are arranged in two respective parallel planesalong respective circular paths T having the same diameter, centred onthe rotation axis R. The number of magnetic elements 16 is differentfrom that of the magnetic elements 16′: in the example shown, themagnetic elements 16 are thirteen, and the magnetic elements 16′ aretwelve. Moreover, the magnetic elements 16 are arranged at a regularmutual angular distance, whereas the magnetic elements 16′ are arrangedat different mutual angular distances.

Referring to the illustration in FIG. 7, the magnetic elements 16,16′ ofthe two sets 12,14 are arranged in such a way that when a magneticelement 16′ of the one set 12 is aligned and geometrically overlappedwith a respective magnetic element 16 of the other set 14 along an axisthat is parallel to the rotation axis R, all other magnetic elements areoffset with respect to one another in order to reduce/eliminate themagnetic forces acting in the direction opposite to the rotationdirection V.

As a result, the aforesaid offset arrangement allows to avoid that allmagnetic elements of one set simultaneously couple/decouple with/fromthe elements of the other set, and, consequently, that they brake orslow down the rotation of the flywheel.

In other words, since at any moment there is only one element 16′positioned in front of the respective magnetic element 16, magneticrepulsions are consequently reduced, as the magnetic elements alreadydecoupled are not subject (or are less strongly subject) to a return inthe direction opposed to the rotation direction V.

The kinetic accumulator 1 comprises a flywheel drum 36, in rotatingconnection with the flywheel 4, out of which there is made a housingseat 38 in which the magnetic elements 16′ of the flywheel 4 are fitted.

The flywheel drum 36 may be made at least partially from a magneticallyinert material, advantageously from a polymer material optionally loadedwith reinforcing fibres.

Merely by way of example, the magnetically inert material may comprise acomposite material based on polylactic acid (PLA) and glass fibre.

The flywheel drum 36 provides first coupling members of the magneticelements 16′, arranged at the housing seat 38 of the magnetic elements16′.

In particular, each magnetic element 16′ is provided with a metalthreaded coupling pin 40 integrated therein, especially screwed in amagnetically inert material of said drum 36.

More specifically, each pin 40 provides a portion that is magneticallyattractable by the magnetic element 16′, to retain said element 16′ insaid seat 38 through the magnetically active action of the element 16′itself.

The accumulator assembly 2 defines a seat 62 in which the magneticelements 16 are housed.

The seat 62 is made out of the assembly wall 34. The seat 62 extendsannularly about the rotation axis R.

At the seat 62, the accumulator assembly 2 provides second couplingmembers incorporated in a magnetically inert material of said assembly.

More specifically, the second coupling members provide a punched annularflange 64 in whose holes there is fitted a set of metal threaded pins 66that are screwed in the seat 62. Each threaded pin 66 is a portionmagnetically attractable by a corresponding magnetic element 16 toretain said element 16 in said seat 62 through the magnetically activeaction of the element 16 itself.

The accumulator 1 also provides means 22 for adjusting the axialdistance between the two sets 12,14 of magnetic elements 16,16′, andthus the width of the magnetic support space 18.

In other words, by adjusting the axial distance it is possible todetermine the repulsive force between the two sets of magnets, based onthe weight load with which the flywheel 4 is intended to rest on themechanical rolling means 6,8.

The adjustment means 22 are formed by a hole 24 made out of the flywheeldrum 36 and having a threaded portion 28 cooperating with acomplementary threaded portion 30 arranged at the rotation shaft 26, orarranged at the set 12 of magnetic elements 16′ associated to theflywheel 4. By rotating the flywheel drum 36 with respect to therotation shaft 26 it is possible to adjust the axial distance betweenthe two sets of magnets. Next, the flywheel drum 36 may be held on therotation shaft 26, in the position required, by means of one or moreradial pins, not shown.

FIGS. 8-10 show a flywheel kinetic accumulator similar to theaccumulator 1, but with a different adjustment of the axial distance. Inthese Figures, some parts of the accumulator assembly 2 are omitted. Theflywheel kinetic accumulator as shown in FIGS. 8-10 is genericallyindicated with 100.

The accumulator 100 also provides a base wall 134, having an annular setof magnetic elements 116 being disposed in a seat 162 thereof, andpivotally supporting a flywheel 104 having another set of magneticelements 116′ mounted thereon.

In this case, too, it is provided that the magnetic elements 116 arefixed to the flywheel 104 by means of threaded pins, and that themagnetic elements 116′ are fixed to the base wall 134 by means of both apunched annular flange 164 and some threaded pins 166. In this case,however, the assembly consisting of magnetic elements 116′, flange 164and pins 166, is mounted on a plate 170 housed in a lower seat 171 ofthe base wall 134. The plate 170 is provided with a threaded shank 172that is screw-coupled with an internally threaded bush 173 fixed to thebase wall 134 by means of an additional plate 174. By rotating the plate170, such plate is either lifted or lowered in the seat 171, so as tolift or lower the magnetic elements 116, and adjust the axial distancebetween the two sets of magnets 116,116′. Next, the plate 170 is held inthe required position by means of a nut, not shown, which is screwed tothe free end of the threaded shank 172 and stops against the bush 173.

FIG. 11 shows the magnetic elements 116 in detail. These magneticelements 116 have a cylindrical shape, are thirteen, and are arrangedalong a circular path having a diameter D intersecting the axes of themagnetic elements 116. Moreover, the magnetic elements 116 are arrangedat the same angular distance with respect to each other, in this example28°.

FIG. 12 rather shows the magnetic elements 116′ in detail. Thesemagnetic elements 116′ also have a cylindrical shape, but are twelve,and are arranged along a circular path always having a diameter D—as theprevious one—intersecting the axes of these magnetic elements 116′.Unlike the magnetic elements 116, however, the magnetic elements 116′are arranged at different angular distances, in this example rangingfrom 28° to 32°.

The kinetic accumulators described above are suitable for overcoming thedrawbacks reported above.

More specifically, the accumulators illustrated above allow to reduce oreliminate the magnetic return forces acting between magnets of oppositesets, so as to store higher quantities of energy—all other featuresbeing equal—than the systems currently in use.

Advantageously, the accumulators described above have been designed towork at ambient pressure, thus abandoning any expensive systems for thegeneration or maintenance either of a vacuum or of pressurization.Advantageously, the accumulators described above allow to achieve anoffset arrangement of the magnets in a simple, rational way.

Advantageously, the accumulators described above provide an adjustmentsystem that is very rapid to use, and robust, thanks to its simpleconstruction.

Advantageously, the accumulators present a magnet fixation system whichrequires no special processing, but which turns out to be extremelyadvantageous thanks to the magnetic action employed.

Advantageously, in the accumulators described above the parts adjacentto the magnets are not influenced by the field thus generated, and in noway affect the magnetic support of the flywheel.

Advantageously, the accumulators described above may utilize lubricatedor non-lubricated rolling means, without distinction, depending on thecircumstances. Advantageously, the accumulators described above aresuitable for being rapidly adjusted or modified, so as to cope with anychanged design needs.

The elements forming part of the embodiments of the kinetic accumulatorsdescribed above may be changed or substituted with other functionallyequivalent ones by those skilled in the art, in order to meet specialneeds.

These variations, too, fall within the scope of protection as defined bythe following claims.

Moreover, each variation described as belonging to a possibleembodiment, may be implemented independently of any other variationdescribed.

1-17. (canceled)
 18. Flywheel kinetic accumulator comprising: anaccumulator assembly; a flywheel, arranged in said assembly so as torotate about a rotation axis in a desired rotation direction, mechanicalrolling elements, mounted between the accumulator assembly and theflywheel, for guiding the rotation of the latter, magnetic supportelements of the flywheel, comprising at least two sets of magneticelements facing each other and magnetically interacting with each other,arranged in two respective parallel planes, along two respectivecircular paths having the same diameter, at a distance from each otheraround said rotation axis, said sets being one connected to theaccumulator assembly and the other to the flywheel, and defining amagnetic support space therebetween, wherein the magnetic elements ofthe two sets are arranged such that when a magnetic element of the oneset is aligned and geometrically overlapped with a respective magneticelement of the other set along an axis that is parallel to the rotationaxis, all other magnetic elements are offset with respect to one anotherin order to reduce/eliminate the magnetic forces acting in the directionopposite to the rotation direction.
 19. Kinetic accumulator according toclaim 18, wherein one of said sets comprises a number of magneticelements that is different from the number of magnetic elements of theother set.
 20. Kinetic accumulator according to claim 18, wherein: themagnetic elements of one of said sets have a regular mutual angulardistance; the magnetic elements of the other of said sets have adifferent mutual angular distance with respect to one another. 21.Kinetic accumulator according to claim 18, wherein the magnetic elementsidentify magnet surfaces facing each other and defining the magneticsupport space, and having substantially the same conformation for bothsets.
 22. Kinetic accumulator according to the claim 18, wherein whenthe magnetic element of one set is aligned with the respective magneticelement of the other set, a single pair of magnet surfaces isoverlapping and coinciding in a direction substantially parallel to therotation axis.
 23. Kinetic accumulator according to claim 18, whereinthe set of magnetic elements associated with the flywheel is movablealong a circular path centred on the rotation axis, and wherein the setof magnetic elements associated with the accumulator assembly isdistributed along the same path.
 24. Kinetic accumulator according toclaim 18, wherein the sets of magnetic elements have the same polarity,so as to repel each other along the rotation axis or parallel thereto.25. Kinetic accumulator according to claim 18, comprising an arrangementfor adjusting the distance between the two sets of magnetic elements.26. Kinetic accumulator according to claim 25, wherein the adjustmentarrangement comprises a hole made out of the flywheel drum and providedwith a threaded portion cooperating with a complementary threadedportion arranged at the rotation shaft.
 27. Kinetic accumulatoraccording to claim 25, wherein the adjustment arrangement comprises asupport plate for a set of magnetic elements housed in a base wall ofthe accumulator assembly, wherein the plate is provided with a threadedshank that is screw-coupled with an internally threaded bush fixed tothe base wall.
 28. Kinetic accumulator according to claim 18, comprisinga device for detecting the weight of the flywheel, releasably fittedthrough an access opening to an inner space, made out of a base wall ofsaid accumulator assembly, for example, to detect the load resting onthe mechanical rolling elements.
 29. Kinetic accumulator according toclaim 18, comprising a flywheel drum, in rotating connection with theflywheel, that defines housing seats in which the magnetic elements ofthe flywheel are at least partially fitted, the said drum optionallybeing made at least partially from a magnetically inert material. 30.Kinetic accumulator according to claim 18, wherein at one or morehousing seats of the magnetic element the flywheel drum comprises firstcoupling members at least partially incorporated in a magnetically inertmaterial of said drum, wherein the first coupling members comprise aportion that is magnetically attractable by the magnetic element, toretain said element in said seat.
 31. Kinetic accumulator according toclaim 18, wherein the accumulator assembly comprises a base wall out ofwhich there is made one or more housing seats for the magnetic element,wherein the base wall comprises second coupling members incorporated atleast partially in a magnetically inert material of said housing seat,wherein the second coupling members comprise a portion that ismagnetically attractable by the magnetic element, to retain said elementin said seat.
 32. Kinetic accumulator according to claim 18, wherein therotation axis is oriented in an approximately vertical direction, andwherein the magnetic support elements are designed to magneticallysupport at least part of the weight load of said flywheel acting on themechanical rolling elements.
 33. Kinetic accumulator according to claim18, wherein: the mechanical rolling elements comprise spherical orcylindrical bodies made at least partially from a magnetically inertceramic material; and the magnetic elements comprise a plurality ofpermanent magnets, optionally comprising neodymium.
 34. Kineticaccumulator according to claim 18, wherein the accumulator assemblydefines an outwardly open inner space, at atmospheric pressure, in whichthe flywheel is rotatable.